#include <stdio.h>
#include <string.h>
int a = 10;
int b = 20;

int main()
{
    size_t n = strlen("hello");
    printf("hello world\n");
    int x = 30;
    int y = 40;
    int z = x + y;
    printf("result: %d\n", z);
    return 0;
}


